The fall of the Alamo and the losses in South Texas opened the way for the Mexican army to move farther into Texas. Santa Anna ordered his troops to burn every settlement in their path. He believed that the Texas rebellion was crushed. Sam Houston, however, knew that the Texas campaign was not over. As commander in chief, he ordered the Texas volunteers to retreat eastward. Houston's forces grew in number as volunteers arrived from the United States. Most were untrained and poorly equipped, so Houston continued to retreat and to train the army in the fundamentals of warfare. As Santa Anna's troops pursued the leaders of the Texas government, Houston moved his army toward the San Jacinto River. On April 18, the Texas soldiers camped along the banks of Buffalo Bayou to meet the Mexicans.

Victory at San Jacinto On April 20, Santa Anna's army camped on the edge of the prairie that faced Houston's camp. The next afternoon, while Santa Anna, General Cós, and their men were resting, Houston issued the order to attack. The Texans moved across the open prairie and opened fire with rifles and cannons. The battle lasted 18 minutes, but the killing continued until dark as the Texans cut down Mexican soldiers who had fled into the swamps.

Fewer than 10 Texans were killed or fatally wounded in the Battle of San Jacinto. General Houston listed 630 Mexicans killed and 730 taken prisoner. One of the prisoners was Santa Anna. He signed two treaties with the Texas government. In the public treaty, he promised to never fight the Texans again and ordered all Mexican forces out of Texas. In the secret treaty, Santa Anna promised to work for Mexican recognition of Texas independence.

News of the amazing victory soon spread throughout Texas. The settlers who had fled their homes returned. President David Burnet and Vice President Lorenzo de Zavala faced the task of organizing the new Republic of Texas.